1. Field of the Invention
The present invention generally relates to a lamp and a heat sink thereof and, more particularly, to an embedded lamp utilizing a fan to trigger air flow for ventilation, as well as a heat sink thereof.
2. Description of the Related Art
Taiwan Patent Number M330426 discloses a conventional lamp as shown in FIG. 1. In FIG. 1, the lamp as shown is 180 degree inversed relative to an assembly direction. The lamp has a cooling base 81, a circuit board 82, a light-emitting diode (LED) module 83, a cooling fan 84 and a lamp head 85. The cooling base 81 has a concave portion 811 and a receiving portion 812. The circuit board 82 and LED module 83 are received in the concave portion 811. The cooling fan 84 is received in the receiving portion 812. The lamp head 85 is coupled to an outer portion of the receiving portion 812. The cooling base 81 includes a plurality of heat-dissipating holes 813 extending into the receiving portion 812. The lamp head 85 includes a plurality of vents 851 into which external air is drawn. During operation of the lamp, the external air is drawn into the receiving portion 812 via the vents 851 and then exhausted out of the receiving portion 812 via the heat-dissipating holes 813 for dissipating the heat generated by the lamp head 85.
When in use, the lamp head 85 is coupled to a lamp seat; and the vents 851 and the heat-dissipating holes 813 are made in contact with the external air so that air inside the receiving portion 812 is allowed to exchange with the external air. However, the vents 851 where the external air is drawn into the receiving portion 812 are located in a relatively upper portion of the lamp where heat air tends to gather (this is because that in thermal convection theory heat air tends to float around higher areas than cool air). Hence, the exhausted heat air from the heat-dissipating holes 813 tends to gather around the relatively upper portion of the lamp and is therefore re-drawn into the receiving portion 812 via the vents 851, leading to degradation of cooling efficiency. Furthermore, when the lamp is inserted into a “plate-type” ceiling (meaning the ceiling that is assembled from a plurality of square plates) for artistic consideration, the heat-dissipating holes 813 and the vents 851 are settled right above the plate-type ceiling, and only the LED module 83 and its related portions remain beneath the plate-type ceiling for illumination purpose. However, since the area above the plate-type ceiling is an enclosed space with poor air circulation, poor heat dissipation is therefore resulted. As a result, service life of the lamp is shortened.
Taiwan Patent Number M346745 discloses another conventional lamp as shown in FIG. 2. Referring to FIG. 2, the lamp includes an upper casing 91, a lower casing 92, a heat-dissipating assembly 93 and a LED assembly 94. The upper casing 91 includes a receiving room 911 in which the heat-dissipating assembly 93 and LED assembly 94 may be disposed. The upper casing 91 and lower casing 92 together may form a housing of a lamp. The upper housing 91 includes a plurality of vents 912 and the lower housing 92 includes a plurality of through-holes 921. When a cooling fan 931 of the heat-dissipating assembly 93 is operated, the external air is drawn into the receiving room 911 via the vents 912 and then exhausted out of the receiving room 911 via the through-holes 921 for dissipating the heat generated by the LED assembly 94.
However, the vents 912 are still located in a relatively upper portion of the lamp where the heat air exhausted from the through-holes 921 tends to gather. As a result, the heat air is re-drawn into the lamp via the vents 912, affecting the cooling efficiency of the lamp. Although the through-holes 921 are made in contact with the external air when the conventional lamp is inserted into the plate-type ceiling, the cooling efficiency of the lamp is not improved enough since the vents 912 are still located in the enclosed space right above the plate-type ceiling.
Therefore, it is desired to improve the conventional lamp.